Method of making lively thermoplastic yarn



' May 29, 1962 N. J. STODDARD ET AL 3,036,423

METHOD OF MAKING LIVELY THERMOPLASTIC YARN Original Filed Jan. 4, 1954 4 Sheets-Sheet 1 FIGI.

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' May 29, '1962 N. J. STODDARD ET AL 3,036,423

METHOD OF MAKING LIVELY THERMOPLASTIC YARN Original Filed Jan. 4, 1954 4 Sheets-Sheet 2 INVENTORS NICHOLAS J. STODDARD WARREN A. SEEM BY mm FIG. 2.

ATTYS.

May 29, 1962 N. .1. STODDARD ET AL ,4

METHOD OF MAKING LIVELY THERMOPLASTIC YARN Original Filed Jan. 4, 1954 4 Sheets-Sheet 3 INVENTORS; NICHOLAS J. STODDARD WARREN A. SEEM ATTYS.

y 1962 N- .1. STODDARD ET AL 3,036,423

METHOD OF MAKING LIVELY THERMOPLASTIC YARN 4 Sheets-Sheet 4 Original Filed Jan. 4, 1954 F'IGA INVENTORS:

NICHOLAS J. STODDARD WARREN A. SEEM United States Patent 3,036,423 NIETHOD 0F 1 1 .-l LIVELY THERMO- PLASTIC YARN Nicholas J. Stoddard, Berwyn, and Warren A. Seem, Chester Springs, Pa., assignors, by mesne assignments, to Universal Winding Company, Cranston, R.ll., a corporation of Massachusetts Original application Jan. 4, 1954, Ser. No. 401,951, now Patent No. 2,803,109, dated Aug. 20, 1957. Divided and this application Aug. 8, 1957, Ser. No. 677,149

1 Claim. (Cl. 57-157) This invention relates to thermoplastic yarns such as nylon, vinyon, Orlon, Velon, Dacron, saran, and the like (as distinguished from silk, rayon, cotton, linen or wool, etc.), and is a division of our application Serial No. 401,951, filed January 4, 1954 (now Patent No. 2,803,- 109).

Thermoplastic yarns of the kind referred materially respond to shrinking by becoming more ductile or plastic and thermally stabilized in cooling which, after subjected to the action of heat assume new and substantially permanent physical characteristics when twisted, stretched or shrunk while heated. The invention is especially concerned with the production of monofilament yarns having useful active and latent torsional force permanently imparted thereto.

The above objective is broadly realized through the utilization of our method of thermally processing fully disclosed in a separate US. application Serial No. 40 1,- 803, filed January 4, 1954 (now Patent No. 2,803,108), in combination with our herein disclosed method of utilizing the apparatus of the attached drawings, wherein:

FIG. 1 is a fragmentary view, in front elevation of one form of apparatus suitable for carrying out our improved method of producing thermoplastic yarns having various improved physical characteristics;

FIG. 2 is a fragmentary view of the apparatus of FIG. 1 in cross section.

FIG. 3 is a fragmentary View in section taken as indicated by the angled arrows IIIIII in FIG. 1, drawn to a larger scale and showing a specially constructed heating unit embodied in the apparatus;

FIGS. 4, 5 and 6 respectively, are a front view, a side elevation and a top plan view likewise drawn to a larger scale, of a specially constructed tensioning device embodied in the apparatus; and

FIG. 7 is a large scale axial sectional view of a specially constructed twisting and untwisting spindle also embodied in the apparatus.

Referring to FIGS. 1 and 2 of the drawings, there is shown apparatus which is basically known in the textile art as an up-twister such as is ordinarily employed in twisting yarns. One of the usual guides for distributing the processed yarn upon the corresponding revolving take-up spool S is indicated at 3, the usual traverse bar for the guide at 4, the usual roll for driving the spool at 6, the usual driven shaft for the roll at 7, and the usual spindle driving belt at 8.

A special overhead creel 9 is provided for supporting the package P of thermoplastic yarn Y which is to be processed along with a specially constructed heating device 10, a specially constructed yarn tensioning device 11, and a specially constructed twisting and untwisting spindle 2. As shown, the heating device 10 and the tensioning device 11 are vertically arranged, the latter above the former, in the vertical interval between the spindle 2 and the take-up spool S.

As later on explained, the device 10 is electrically heated, current being conducted to it through two fixed horizontally-arranged bus bars 12 and 13 whereto said device is secured, with interposition of insulating bushings 3,036,423 Patented May 29, 1962 14 as shown in FIGS. 2 and 3, by screws 15 and 16. The required degree of heat is uniformly maintained in the device by current at a constant voltage (not exceeding twenty-four volts for personal safety) through an automatic induction voltage regulator 17 from a power line 18, 19, said regulator being connected by conductors 20, 21 to a manually-adjustable induction voltage regulator 22 connected, in turn, by conductors 23, 24 to the primary of a step down transformer 25 in circuit through conductors 26, 27 with the bus bars 12, 13.

The output voltage of the induction voltage regulator 17 is automatically governed by a thermally responsive sensing means 28 incorporated in the heating device 10. The automatic and manual induction voltage regulators 17 and 22 and the thermostatic sensing means 28 may all be of any approved standard commercially available types through cooperation of which the temperature in the heating device 10 is modulated compensatively with changes in ambient or room temperature and the rate of transfer of heat therefrom to the yarn travelling thereto. Also included in the lines 18, 19 and 20, 21 respectively, are manually operable safety hand switches 29 and 30.

With reference now to FIG. 3, it will be seen that the heating device comprises a central tube 32 which, it is to be understood, is of non-ferrous material and of small diameter and bore, and through which the yarn Y is passed; said tube being provided exteriorly with a thin coat 33 of glass or other insulating material, and surrounded by a coil 34 of resistance wire. As further shown, tube 32 is embedded in a thick walled jacket 35 of thermal insulation, which may be of fiber glass or the like, encased in a metallic shell 36. At its opposite end the shell 36 is closed by sealed covers 37 which may also be of metal, with interposition between them and the insulation, of disks 38 formed from transite or the like to minimize thermal transfer' from the hot tube through said shell to the exterior and vice versa. Engaged over the opposite ends of tube 32 and extending through the disks 38, are hard wear-resistant bushings 39 of porcelain or the like which prevent cutting of the tube by the passing yarn.

It is to be particularly noted that the winding pitch of heating coil 34 increases progressively from the bottom end of tube 32 at which the yarn enters to the midheight of the tube, and then progressively decreases at a corresponding rate toward the end at which the yarn emerges. Accordingly, a greater amount of electrical energy is available at the entrant and the exit ends of tube 32, thereby insuring uniform heat distribution and making possible the use of a much shorter tube than otherwise would be required. The lead 40 from one end of the coil 34 is extended through the insulating jacket 35 to screw 15, and the lead '41 from the other end of said coil to the screw 16, and interposed in lead 40 is a manually operable switch which is diagrammatically indicated at 42. The tensioning means 11 is supported at the upper end of a vertical bracket bar 51 which is secured to the bus bars 12 and 13 by the screws 15 and 16 and insulated therefrom by the bushings 14. The pigtail guide indicated at 53 has its shank extending through a vertical slot 50 in the lower end of the upright bracket bar 51 so as to be vertically adjustable in the interval between the heating device 10 and the spindle 2, said guide being securable in adjusted positions by the clamp nuts indicated at 54.

As shown in FIGS. 4, 5 and 6, the tensioning device 11 comprises two comb-like vanes 55 and 56 between the alternating tines of which the yarn Y is passed. Vane 55 is fixedly supported between a pair of vertically-spaced forwardly-projecting lugs 57 of a bracket plate 58, while vane 56 is swingable about a hinge pin 59 between another pair of vertically-spaced forwardly-projecting lugs 60 The lower or distal end of lever 62 bears against a screw.

65 threadedly engaged in plate 58. By means of screw 65, it is possible to vary the force of the spring 61 and, in turn, the pressure exerted by the wing 56 upon the yarn Y to regulate the drag or tension imparted thereto. The jam nut at 66 serves as a means for securing the screw 65 against accidental displacement in adjusted position.

As shown in FIG. 7, the spindle 2 comprises an upright tube 75 of small diameter and bore which is rotatively supported at its lower end by a pair of vertically-spaced anti-friction ball bearings 76 and 77. These bearings are housed within a cylindric holder 78 set into a retractable arm 79 which is swingably connected in the usual manner from the fixed horizontal rods 86 in the lower part of the apparatus, and which is normally maintained in the position shown by a torsion spring 81 with the tube in tangential contact with the driving belt 8. Freely revolvable about a transverse pin at the upper end of the tube 75 is a small inset 'V grooved reverse twisting roller 82 around which the yarn Y is wrapped one or more times before passing downward through the tube. Being of small diameter and thin walled, the spindle tube 75 is light in weight and dynamically balanced, and can therefore the tube 32 of heating device 10, then through the pig tail guide 53, then'through the spindle 2, then horizontally under a pair of spaced rolls'89 and 99 on a bracket arm 91 reaching forward from the rods 80, then upwardly over afixed longitudinal guide rod 92 to the traverse guide 3, and finally to the driven take-up spool S.

We have herein described and shown in the drawings a conventional tip-twister converted to carry out our methods of processing, but any type of twisting machine may be similarly converted or a machine specially constructed for the purpose. The essential elements of apparatus for producing the yarn are (l) a yarn supply creel, (2) a. restricted isolated heated zone capable of regulation to uniformly heat a travelling yarn up to the melting point of the yarn, (3) means for cooling the heated yarn;

(4) a'yarn tensioningmeans capable of adjustment to.

uniformly apply correlated yarn tension up to the breaking point of the yarn, (5) 2. driven twisting-untwisting spindle such as herein described, and (6) a driven takeup package. V V V For the purposes of illustration, let it be assumed that the yarn Y is in the form. of a continuous 'monofilarnent of nylon or the like. As the yarn continually passes down: through the heating device 10 it is uniformly heated toa temperature within twenty degrees of the melting point of the thermoplastic. This temperature is predetermined by adjustment of the manual induction voltage regulator 22 in accordance with the uniformlin ear speed at which it is travelled, the temperature beingautomatic-ally modulated compensatively with changes in ambient or. room temperature and the rate of transfer. of heat to the travelling yarn by action of the sensing means Zfiupoh the" automatic induction voltage regulator 17, and the device 11 being adjusted to maintain the-yarn under unlform tension correlated to the temperature to which the yarn is heated and the linear speed of travel of the yarn.

While in a heated plasticstate, the yarn is twisted and heat-set in one direction as it traverses the restricted heated zone of the heating device It by the action of the rapidly revolving spindle 2. Subsequent cooling is eflected by ballooning as the yarn advances downward in the interval between the outlet end of the tube 32 of said heating device and the wheel 82, the yarn being reoriented or realigned therein according to the twisted wrapped for positive control, one or more times about the small wheel 82 of the untwisting spindle 2 as previously explained, and the cooling being promoted by contact of the yarn with the face of the wheel 82 and the smooth sloping groove sides of said wheel. By action of the transverse rotation or movement of the wheel 82, the yarn is reversely twisted as it loses frictional contact with wheel 82 and passes down through the tube 75 of the spindle to the guide wheel 89- and after rounding the latter and the guide wheel 90, it travels upward and after passing over the-rod 92 and the traverse guide 3 it is continually taken up by the revolving spool S.

As a result of this continuous processing by means of which the yarn is twisted and heat-set and then twisted in the reverse direction monofilament yarn is produced which is delustered and has permanently set or imparted therein useful active and latent torsional force. By this is meant that the yarn is yarn-set, that is, the molecules in the thermoplastic yarn are permanently and uniformly formation of the yarn at the time of yarn-setting so that the yarn has an inherent tendency to twist uniformly and assume the twisted formation which it had at the time of yarn-setting.

We claim:

The method of making monofilament thermoplastic yarn having permanent active and latent torsional forces therein which comprises, continually drawing a monofilament thermoplastic yarn from a supply, continuously twisting the yarn in one direction, continually passing the yarn at a selected linear speed under uniform tension through a restricted thermally isolated and uniformly heated zone to uniformly heat the yarn to a prescribed temperature to reorient the molecules of the yarn to the twisted formation of the yarn and yarn-set the same, controlling the supply of heat energy to said zone to thereby maintain said heated zone uniformly at the temperature required to uniformly heat said yarn to said prescribed temperature, continually cooling the yarn to stabilize the same after passage under tension through said heated zone, and continually untwisting the yarn after cooling the same to establish therein permanent active and latent torsional forces providing an inherent tendency for the yarn to twist and assume the formation which it had at the time of yarn-setting.

References Cited in the file of this patent UNITED STATES PATENTS Ubbelohde Dec. 9, 1958 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,036,423 May 29, 1962 Nicholas J. Stoddard et a1.)

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the grant, lines 2 to 4, for "assignors, by mesne assignments, to Universal Winding Company, of Cranston, Rhode Island, a corporation of Massachusetts, read assignors, by mesne assignments, to Leesona Corporation,

a corporation of Massachusetts, line 13, for "Universal Winding Company, its successors" read Leesona Corporation, its successors in the heading to the printed specification,

lines 5 to 7, for "assignors, by mesne assignments, to Universal Winding Company, Cranston, R. 1., a corporation of Massachusetts" read assignors, by mesne assignments, to Leesona Corporation, a corporation of Massachusetts Signed and sealed this 25th day of December 1962.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents 

